Genetic variants of CSN1S1, CSN2, CSN3, and BLG genes and their association with dairy production traits in Sahiwal cattle and Nili-Ravi buffaloes

Milk protein genes are associated with milk yield and composition in dairy animals. The present study aimed to identify milk protein genes (CSN1S1, CSN2, CSN3, and BLG) genetic variants and their association with milk yield in Sahiwal cattle and Nili-Ravi buffaloes. One hundred animals from each species were selected to collect blood samples and milk production records. Primers were designed for these milk protein genes for PCR amplification. Sequencing of resultant PCR products revealed a higher number of SNPs (13 vs. 7, 5 vs. 1, and 6 vs. 2) in Sahiwal as compared to Nili-Ravi animals in CSN1S1, CSN2, and CSN3 genes, respectively. However, a single SNP was observed in BLG gene of both species. Association analysis revealed that one SNP in BLG gene of Nili-Ravi was associated (p < 0.05) with 305-day milk yield. Two SNPs at CSN1S1 gene in Sahiwal were associated with dry-period. Similarly, one SNP at CSN1S1 and two SNPs at CSN3 gene showed significant association (p < 0.05) with average calving-interval in Sahiwal while two SNPs in CSN1S1 gene were associated (p < 0.05) with this trait in Nili-Ravi. These SNPs could be helpful as candidate variants for marker-assisted selection in cattle and buffaloes for improvement of lactation performance.

Molecular characterization of Mycobacterium bovis infection in cattle and buffalo in Amazon Region, Brazil

The aim of this study was to characterize Mycobacterium bovis from cattle and buffalo tissue samples, from two Brazilian states, and to analyse their genetic diversity by spoligotyping. Tissue samples from tuberculosis suspect animals, 57 in Amazonas State (12 cattle and 45 buffaloes) and six from Pará State (5 cattle and one buffalo) from slaughterhouses under State Veterinary Inspection, were isolated in culture medium Stonebrink. The positive cultures were confirmed by PCR and analysed by the spoligotyping technique and the patterns (spoligotypes) were identified and compared at the Mycobacterium bovis Spoligotype Database (http://www.mbovis.org/). There was bacterial growth in 44 (69.8%) of the tissues of the 63 animals, of which PCR for region of differentiation 4 identified 35/44 (79.5%) as Mycobacterium bovis. Six different spoligotypes were identified among the 35 Mycobacterium bovis isolates, of which SB0295, SB1869, SB0121 and SB1800 had already been described in Brazil, and SB0822 and SB1608 had not been described. The most frequent spoligotype in this study (SB0822) had already been described in buffaloes in Colombia, a neighbouring country of Amazonas state. The other identified spoligotypes were also described in other South American countries, such as Argentina and Venezuela, and described in the Brazilian states of Rio Grande do Sul, Santa Catarina, São Paulo, Minas Gerais, Mato Grosso do Sul, Mato Grosso and Goiás, indicating an active movement of Mycobacterium bovis strains within Brazil.